Active rectifiers produce DC power having desired current and voltage characteristics from an AC source. It is known to circulate a variable current proportional to a load current on the DC bus to the active rectifier and to control voltage on the DC bus by adjusting a power factor input to the active rectifier as the DC load current varies. However, it is has been found that certain types of equipment, such as a switched reluctance machine for starting a main aircraft engine, can produce a large amount of current harmonics and may cause oscillations on the DC bus.
Known controllers cannot adequately control DC bus voltage in the presence of such current fluctuations unless the level of recirculating current is increased significantly. Such an increase in recirculating current will lead to higher power losses and require a larger, heavier device. Increasing the power output and weight of the device is particularly undesirable in the aircraft systems where such switched reluctance machines may be found, especially in view of the fact that these current oscillations are generally transient in nature. It is especially undesirable to provide a heavier, more costly system merely to address such transient conditions.